1. Field of the Invention
This invention relates generally to carriers for supporting equipment externally on a vehicle.
2. Prior Art
Equipment too large for being carried inside a vehicle, such as wheelchairs, bicycles, and cargo boxes, may be supported on carriers attached to the rear of the vehicle. Some carriers are bolted directly to the vehicle, and others are attached to a conventional trailer hitch.
U.S. Pat. No. 5,664,717 to Joder shows an equipment carrier including a horizontal arm with a proximal end for being attached to a trailer hitch on a vehicle. The arm is articulated at two positions for pivoting away from the vehicle's tailgate or backdoor. It is specifically made for carrying bicycles, which must be manually lifted onto the carrier. U.S. Pat. No. 5,456,564 to Bianchini shows an equipment carrier with a platform connected by hinged arms that move through an arc. The arms deploy to a position far behind the vehicle, so that they cannot be deployed when the vehicle is parked closely in front of another vehicle. The arms are retracted to an almost vertical position, so that the carrier is not suitable for carrying a cargo box, because the box would be lifted so high that it would block the rear window of the vehicle. Further, it requires a powerful electric winch, which is very expensive. U.S. Pat. No. 5,114,120 to Bartelt et al. shows another equipment carrier with an articulated arm. U.S. Pat. No. 5,038,983 to Tomososki shows a cargo box and carrier for attaching to a trailer hitch. The box cannot be removed from the carrier. U.S. Pat. No. 5,011,361 to Peterson shows an equipment carrier with an electric screw actuator, which is powerful but very expensive. U.S. Pat. No. 4,844,528 to Johnson shows a rear mounted box for vehicles. It includes four retractable legs with wheels on the lower ends. The legs are individually operated, so that they are easily set to incorrect lengths by mistake, especially over uneven ground. U.S. Pat. No. 4,695,218 to Boyer shows another equipment carrier with an expensive screw actuator. U.S. Pat. No. 4,400,129 to Eisenberg et al. shows an equipment carrier with a spring-loaded pivoting arm which is limited to relatively light loads. Equipment carriers sold under the trademark "PIGGYBACK" by VenturCraft, and "DOTX" by Dotronix are cargo boxes mounted on articulated arms, but the boxes must be manually lifted onto and off the arms. Once removed from the arms, the boxes must be carried by hand. Because prior art equipment carriers protrude far behind the vehicle, the driver cannot accurately judge the clearance behind them when backing up, so that they can be easily damaged.